Influence of cation substitution on the complex structure and luminescent properties of the Zn_kIn_2O_(k+3) system

©2020 American Chemical Society This work was supported by the Spanish Ministry of Innovation, Science and Technology and Spanish Ministry of Economy through Research Projects MAT2014-54372-R, MAT2017-82252-R, RTI2018-097195-B-I00 and PCIN-2017-106. This work is partially supported by ShanghaiTech ChEM under the grant number EM02161943. We thank the National Facility ELECMI ICTS and CAI for nuclear magnetic resonance (UCM) and XRD (UCM) facilities. J.B. and A.T.P. acknowledge financial support from the Comunidad de Madrid through the Talento fellowship 2017-T2/IND-5617 and PR65/19 Research Project, respectively.
The effect of In^(3+) substitution by Ga^(3+) or Al^(3+) on the structure and luminescent properties of Zn_7In_(2-x)M_xO_10 (M = Ga or Al; 0 <= x <= 1) oxides has been investigated by means of high spatial resolution X-ray spectroscopy and high-angle annular dark-field images, combined with magic angle spinning nuclear magnetic resonance spectroscopy. Local structural variations have been identified for the Al- and Ga-doped samples through the analysis of atomically resolved chemical maps and the identification of their structural environment within the wurtzite lattice. In3+ is distributed in a zig-zag modulation, while Al^(3+) and Ga^(3+) are located in a flat distribution at the center of the wurtzite block. Density functional theory calculations provide unambiguous evidence for the preferential flat location of Ga^(3+) and Al^(3+) associated with the different strains introduced in the structure as a result of their ionic radii. The characterization of the photoluminescence response reveals the appearance of new radiative recombination pathways for the doped materials because of the presence of new defect levels in the band gap of the Zn_7In_2O_10 structure.
Ministerio de Economía y Competitividad (MINECO)
Ministerio de Ciencia e Innovación (MICINN)
Comunidad de Madrid
Depto. de Física de Materiales
Fac. de Ciencias Físicas
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